The field of the invention is numerical control systems for machine tools such as those disclosed in U.S. Pat. Nos. 4,038,533 and 4,228,495, and particularly, means for enabling general purpose numerical control systems to be easily configured to a particular machine tool and means for facilitating the development of part programs for such machines.
When a numerical control system is mated with a particular machine tool, the manufacturer often provides commonly used stored programs which can be called up by the user's part programs. Such stored programs are referred to as "canned cycles" and they perform such repetitive functions as drilling a specified hole pattern, drilling an tapping holes, and other often-repeated turning and milling functions. In addition, some controls allow the user to load such canned cycles from the part program and to make repeated calls to it during the execution of the remainder of the part program.
In prior art numerical controls, stored programs are not general purpose, but are instead, very specific. For example, a canned cycle for drilling a hole pattern would specify the number of holes and their precise spacing with respect to one another. Although the entire hole pattern might be locatable on the part being machined, there were no other variables. As a result, either many canned cycles were stored, or the hole patterns were defined separately in each part program run on the machine.
Another limitation on prior numerical control systems is the inability of the machine operator to change, or edit, canned programs during the execution of a part program. Although part program blocks can be edited "on-line" and entire canned programs can be replaced "off-line", there is no means on prior systems for changing canned program dimensions just prior to running them. For example, it may be desirable just prior to running a canned program to adjust a dimension to account for tool wear.